Go to http://apt.freshrpms.net/ and get the appropriate version for your system. Easiest way to get it: "cd /tmp", "wget <url of rpm>". If you're not sure of your version, use rpm -v and compare to what's on that site. NOTE ON RH AS 2.1 Oddly enough, despite what you might expect, RedHat Advanced Server 2.1 seems to be closer to RH 7.2 then 7.3. If you go with 7.3 in your apt sources list, it will want to upgrade a lot of stuff. Run "rpm -i <the apt rpm file you downloaded>".

You are installing on RH9... you will need an older version of Apache (which is bundled with the xampp download). So download an older version of Xampp.

I downloaded 1.5.0, I haven't had time to try a newer version. Since you are using an older flavor of RH linux, you will need to use the older versions of the LAMP bundle. If you want the latest version, you'll have to update your RH9 with the latest packages that are used by Apache and the like.